Mechanism for controlling the boom arms and bucket of a front end loader

ABSTRACT

Mechanism for operating a pair of boom arms at one speed and operating a bucket pivotally mounted on the boom arms at two different speeds through manipulation of a single control handle. The mechanism includes a first valve connected to the control handle and second and third valves connected by linkage to the control handle for sequential operation.

United States Patent [56] References Cited UNITED STATES PATENTS 6/1959 Pilch Primary Examiner--Gerald M. Forlenza Assistant Examiner-John Mannix [72] Inventor Gel-sen L. Wallace Fargo, N. Dak.

[21] Appl. No. 5,755 [22] Filed Jan. 26, 1970 [45] Patented Oct. 19, 1971 [73] Assignee Clark Equipment Company Attorneys-Kenneth C. Witt, John C. Wiessler, Robert H.

Johnson and Reginald J. Falkowski ABSTRACT: Mechanism for operating a pair of boom arms at one speed and operating a bucket pivotally mounted on the boom arms at two different speeds through manipulation of a single control handle. The mechanism i n R 7 E MD M GA 2 BO E RD N T m G T m WW m L m m T N s 0 m CWF m Km m m MB m ED m NN mmm RC S MA6 U v N h w ncludes a first valve connected to the control handle and second and third valves connected by linkage to the control handle for sequential operation.

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PATENTEnum 19 Ian 3,614,273 SHEET NF 4 GERSEN L. WALLACE PATENTED BT 19 3,614,273 SHEEI 2 OF 4 FIG. 2

I N VIL'N'I'UR GERSEN L'. WALLACE ATTORNEY PATENTEDnm 19 I971 SHEEI M 0F 4 FIG. 5

INVENTUR GERSEN L. WALLACE ATTORNEY MECHANISM FOR CONTROLLING BOOM ARMS AND BUCKET OF A FRONT END LOADER BACKGROUND OF THE INVENTION The field of art to which this invention relates includes controls for multiple fluid motor systems, and more specifically controls for operating two fluid motors simultaneously or independently and connecting one of the fluid motors to one or more sources of pressurized fluid.

An object of my invention is to provide improved mechanism for controlling the boom arms and bucket of a front end loader.

SUMMARY OF THE INVENTION In carrying out my invention in a preferred embodiment thereof, I provide first and second sources of pressurized fluid and a fluid motor. A first valve is connected to the fluid motor to control the supply of pressurized fluid thereto and a second valve is connected to the first valve and the sources of pressurized fluid and is operable to supply pressurized fluid from only one of the sources or both of the sources to the first valve. Further, linkage is connected to the valves for actuating them sequentially.

The above and other objects, features and advantages of my invention will be more readily understood by persons skilled in the art when the drawing is taken in conjunction with the detailed description.

BRIEF DESCRIPTION OF DRAWING FIG. 1 shows a compact front end loader utilizing my invention,

FIG. 2 is a schematic diagram of the hydraulic system for actuating the boom arms and bucket of the vehicle of FIG. I,

FIG. 3 is a cross section of the flow-combining valve embodied in the system shown in FIG. 2,

FIG. 4 is a cross section of the bucket motor control valve embodied in the system shown in FIG. 2,

FIG. 5 is a front view of the linkage for actuating the valves embodied in the system shown in FIG. 2,

FIG. 6 is an end view of the linkage shown in FIG. 3 and FIG. 7 is a plan view of the linkage shown in FIG. 3.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIG. I, the reference numeral 10 denotes a compact front end loader having a body 12 supported by four drive wheels I4 (only three of which can be seen). Fixed to body 12 at the rear thereof is a pair of upwardly extending stanchions 16 to which a pair of boom arms 18 are connected for pivotal movement. Boom arms l8 are raised and lowered by a pair of double-acting fluid motors 20 pivotally connected between stanchions l6 and boom arms 18. Connected to the forward ends of boom anns 18 for pivotal movement is a bucket 22 which is actuated between dump and carry positions by a pair of double-acting fluid motors 24 pivotally connected between boom arms 18 and bucket 22.

Referring now to FIG. 2, the system 26 for controlling fluid motors 20 and 24 will be described in detail. System 26 includes a dual pump 28 driven by the vehicle prime mover (not shown) which draws fluid from a reservoir 30 and supplies pressurized fluid through a valve bank 32 which controls the supply of pressurized fluid to fluid motors 20 and 24. Pump 28 includes an inlet 34 connected to reservoir 30 by a conduit 36 in which a filter 38 is disposed. Pump 28 also includes a 13 g.p.m. section 40 connected to an outlet 42 and a 26 g.p.m. section 44 connected to an outlet 46. Outlet 42 is connected via a conduit 48 to an inlet 50 for valve bank 32 and outlet 46 is connected via a conduit 52 to another inlet 54 for valve bank 32.

Valve bank 32 includes a valve 56 for controlling the supply of pressurized fluid to fluid motors 20, a valve 58 for combining the output of pump sections 40 and 44 and a valve 60 for controlling the supply of pressurized fluid to fluid motors 24.

Valve 56 includes a pair of fluid motor ports 62 and 64 to which fluid motors 20 are connected in parallel by conduits 66 and 68, respectively. With valve 56 in the position shown in FIG. 2, pressurized fluid supplied to inlet 56 is directed through valve 56 to valve 58 and fluid motors 20 are hydraulically locked in place. By shifting valve 56 in one direction away from the position shown, pressurized fluid can be directed to fluid motors 20 to cause them to extend and by shifting valve 56 in the other direction away from the position shown, pressurized fluid can be directed to motors 20 to cause them to retract. Also, valve 56 can be shifted to a position in which the opposite ends of motors 20 are placed in direct communication so that boom arms I8 are free to move when bucket 22 is being pushed along the ground, for example.

Valve 58 functions, in the position shown in FIG. 2, to direct open center flow from valve 56 to valve bank outlet 70 and to connect valve bank inlet 50 to valve 60. Valve 58 can be actuated to another position in which the open center fluid flow through valve 56 from inlet 54 and the fluid flow supplied to inlet 50 is combined and directed to valve 60.

Valve 60 includes a pair of fluid motor ports 72 and 74 which are connected in parallel to fluidl motors 24 via conduits 76 and 78, respectively. With valve 60 in the position shown in FIG. 2, pressurized fluid supplied thereto from valve 58 is directed through valve 60 to valve bank outlet 70 and fluid motors 24 are hydraulically locked in position. Valve 60 may be shifted in one direction from the position shown so that pressurized fluid from valve 58 is supplied to fluid motors 24 to cause them to extend and may be shifted in the other direction from the position shown so that pressurized fluid supplied from valve 58 will cause fluid motors 24 to retract.

At this point it will be clear that valve 56 can be manipulated to supply pressurized fluid to motors 20 to cause them to extend retract, thereby causing boom arms 18 to raise or lower. Also, actuation of valve 60 cause fluid motors 24 to extend or retract, thereby causing bucket 22 to dump or roll back. The speed at which motors 24 extend and retract depends upon whether valve 56 is supplying only the output of pump section or the combined output of pump sections 40 and 44 to valves 60.

Referring now specifically to FIG. 3, valve 58 includes in valve bank 32 a bore 82 in which a spool 84 is slidably disposed. Valve bank 32 includes inlet 50 which communicates with bore 82, a passage 86 which connects the opposite ends of bore 82 with outlet 70 and a fluid passage 88 which connects axially spaced grooves 90 and 92 and bore 82 with valve 60. Spool 84 includes three lands 94, 96 and 98 and a fluid passage 100 which in the position shown, connects a groove 102 in bore 82 with exhaust passage 86. Groove 102, it will be noted, receives pressurized fluid from valve 56. The lands of spool 84 cooperate with the grooves of bore 82 so that in the position shown, groove, 102 is in fluid communication with exhaust passage 86 and port 50 is in fluid communication with passage 88, and hence valve 60. By actuating spool 84 to the right, groove I02 is placed in flUlId communication with passage 88 and communication to exhaust passage 86 through passage 100 is blocked so that the fluid flow supplied to port 50 and the fluid flow supplied to groove I02 are combined and supplied to valve 60 throughpassage 88.

Connected to spool 84 and valve bank 32 is a conventional centering spring mechanism 104 which tends to maintain spool 84 in the position shown and return it thereto when spool 84 is shifted toward the right, for example. Mechanism I04 is arranged so that if spool 84 is shifted toward the right, compression spring 106 is further compressed with the result that when the force on spool 84 is released, spring 106 will extend to its previous position and return spool 84 to the position shown.

Referring specifically to FIG. 4, valve 60 includes a spool I08 slidably disposed in a bore I10 in valve bank 32. It will be seen that the opposite ends of bore I10 are connected to outlet 70 by a fluid passage 112 disposed in valve bank 32. Also, motor ports 72 and 74 communicate with bore 110, as shown. A pair of grooves M4 and 116 are located in bore I10 and inwardly therefrom another pair of grooves '118 and 120 are located. Grooves 114 and 116 are connected by a fluid passage 122. Groove 120 is supplied with pressurized fluid from passage 88 and is connected by a passage 124 and a oneway check valve 126 with passage 122. Groove 118 is connected with outlet 70.

Spool 108 includes four lands 128, 130, 132 and 134 which cooperate with the various passages and grooves communicating with bore 110 so that when spool 108 is in the position shown, pressurized fluid supplied to groove 120 is directed to outlet 70 and fluid communication with ports 72 and 74 is blocked. By shifting spool 108 to the right, fluid communication between grooves 118 and 120 is blocked so that pressurized fluid is directed through passage 124 past check valve 126 and through passage 122 to port 72, and port 74 is placed in communication with passage 112 and hence outlet 80 with the result that motors 24 are caused to extend. By shifting spool 108 to the left, pressurized fluid will be directed to port 74, and port 72 will be placed in communication with passage 112 and hence outlet 70 so that motors 24 will be caused to retract.

Connected between spool 108 and valve bank 32 is a centering spring mechanism 136 which tends to maintain spool 108 in the position shown. Whenever spool 108 is moved away from the position shown, spring 138 of mechanism 136 is com pressed so that when the force which shifted spool 108 is removed, spring 138 will return spool 108 to the position shown.

Springs 106 and 138 are of the same rate so that equal forces are required to shift spools 84 and 108 away from the positions shown in FIGS. 3 and 4. The reason for having this arrangement of spring rates will be explained shortly in conjunction with the linkage for shifting spools 84 and 108.

Turning now to FIGS. 5, 6 and 7, the mechanism 140 for actuating valves 56, 58 and 60 will be explained in detail. Mechanism 140 includes a bifurcated support bracket 142 to which a shaft 144 is connected by a roll pin 146 for pivotal movement about an axis 148. A sleeve 150 is connected to shaft 144 for pivotal movement about an axis 152 which is transverse to and intersects axis 148. Connected to sleeve 150 is a projection 154 to which a control handle 156 is fixed. (While a control handle is shown, it will be understood that projection 154 could be just as easily connected through suitable linkage to a pedal for control by an operator's foot rather than hand.) Also, connected to projection 154 is one portion 158 of a universal joint 160, preferably of the ball and socket type. The other portion 162 of universal joint 160 is connected for pivotal movement by a pin 164 to the spool 166 of valve 56. Universal joint 160 is arranged so that the center of movement thereof lies on axis 148 and is offset from axis 152. Thus, movement of control handle 156 to cause rotation of sleeve 150 results in actuation of spool 166 of valve 56, but movement of handle 156 to cause pivotal movement of shaft 144 about axis 148 does not cause any movement of spool 166.

Shaft 144 is connected to valves 58 and 60 by linkage 168. Linkage 168 includes a link 170 pivotally connected at 172 to spool 108 of valve 60, a link 174 pivotally connected to link 170 at 176 and pivotally connected to spool 84 of valve 58 at 178, and a link 180 pivotally connected at 182 to link 174 and pivotally connected at 184 to shaft 144. It will be noted that the pivot connection 182 is closer to pivot connection 176 than it is to pivot connection 178. Thus, the offcenter position of pivot connection 182 causes a push or pull exerted by link 180 to be divided so that a greater proportion of the force is directed to spool 108 than is directed to spool 84.

lt will now be apparent that linkage 168, together with centering spring mechanisms 104 and 136, provides means for sequentially actuating valves 58 and 60. For example, if control handle 156 is manipulated to cause shaft 144 to move clockwise as seen in FIG. 5, thereby exerting a pull on link 180, this pull will be divided so that a greater proportion will be directed to spool 108 than is directed to spool 84. Since springs 106 and 138 are of the same rate, the result is that spool 108 will move upward as far as permitted by mechanism 104, and then spool 84 will move upward, the extent of upward movement being limited by centering spring mechanism 136. Conversely, by releasing control handle 156 slowly to come back to the position shown in FIG. 5, first spool 84 will return to the centered position and then spool 108 will return to its centered position. Rapid release of control handle 156 to permit it to come back to the position in FIG. 5 permits substantially simultaneous return of spools 84 and 108 to their centered positions.

It will now be clear that by proper manipulation of control handle 156 it is possible to actuate valves 56 and 60 independently of each other or conjointly. Further, through proper manipulation of control handle 156, it is possible to sequentially actuate valves 58 and 60 so that valve 60 is actuated to direct pressurized fluid to motors 24 to cause them to extend, and then actuate valve 58 so as to combine the output flow of pump sections 40 and 44 to thereby increase the rate at which fluid motors 24 extend which results in a very rapid dumping action of bucket 22.

While only a single preferred embodiment of my invention has been disclosed, it will be understood that this description is for purposes of illustration only and that various modifications and changes can be made to my invention without departing from the spirit and scope of it. Therefore, the limits of my invention should be determined from the following appended claims.

lclaim:

1. For use with a vehicle having a body, boom means pivotally connected to the body and load-carrying means pivotally connected to the boom means, the combination comprising first motor means connected to the boom means for raising and lowering the boom means, second motor means connected to the load-carrying means for pivoting the loadcarrying means relative to the boom means, a first source of pressurized fluid, a second source of pressurized fluid, first valve means connected between said first source and said first motor means and operable to actuate said first motor means to cause the boom means to raise or lower, second valve means connected between said second source and said second fluid motor means and operable to actuate said second motor means to cause the loadcarrying means to pivot in either direction relative to the boom means, third valve means connected between said first and second sources and said second valve means and operable to direct only the output of said second source to said second valve means or to direct the combined output of said first and second sources to said second valve means, and means connected to said second and third valve means for sequentially actuating said second and third valve means.

2. The combination as set forth in claim 1 wherein said sequentially actuating means includes first resilient means connected to said second valve means which tends to maintain said second valve means in a predetermined position and second resilient means connected to said third valve means which tends to maintain said third valve means in a predetermined position.

3. The combination as set forth in claim 2 wherein said sequentially actuating means includes linkage means connected to said second and third valve means so that a force applied to said linkage means for actuating said second and third valve means is divided into two forces of different magnitudes and directed to different ones of said second and third valve means.

4. The combination as set forth in claim 2 wherein said sequentially actuating means includes linkage means connected to said second and third valve means, said linkage means including a first link pivotally connected to one of said second and third valve means, a second link pivotally connected to said first link and to the other of said second and third valve means, and a third link pivotally connected to said second link.

5. The combination as set forth in claim 4 wherein the pivotal connection between said second and third links is located between the pivotal connections of said second link to said first link and said other valve means.

6. The combination as set forth in claim 5 wherein the 

1. For use with a vehicle having a body, boom means pivotally connected to the body and load-carrying means pivotally connected to the boom means, the combination comprising first motor means connected to the boom means for raising and lowering the boom means, second motor means connected to the load-carrying means for pivoting the load-carrying means relative to the boom means, a first source of pressurized fluid, a second source of pressurized fluid, first valve means connected between said first source and said first motor means and operable to actuate said first motor means to cause the boom means to raise or lower, second valve means connected between said second source and said second fluid motor means and operable to actuate said second motor means to cause the load-carrying means to pivot in either direction relative to the boom means, third valve means connected between said first and second sources and said second valve means and operable to direct only the output of said second source to said second valve means or to direct the combined output of said first and second sources to said second valve means, and means connected to said second and third valve means for sequentially actuating said second and third valve means.
 2. The combination as set forth in claim 1 wherein said sequentially actuating means includes first resilient means connected to said second valve means which tends to maintain said second valve means in a predetermined position and second resilient means connected to said third valve means which tends to maintain said third valve means in a predetermined position.
 3. The combination as set forth in claim 2 wherein said sequentially actuating means includes linkage means connected to said second and third valve means so that a force applied to said linkage means for actuating said second and third valve means is divided into two forces of different magnitudes and directed to different ones of said second and third valve means.
 4. The combination as set forth in claim 2 wherein said sequentially actuating means includes linkage means connected to said second and third valve means, said linkage means including a first link pivotally connected to one of said second and third valve means, a second link pivotally connected to said first link and to the other of said second and third valve means, and a third link pivotally connected to said second link.
 5. The combination as set forth in claim 4 wherein the pivotal connection between said second and third links is located between the pivotal connections of said second link to said first link and said other valve means.
 6. The combination as set forth in claim 5 wherein the pivotal connection between said second and third links is located nearer to one than the other of said pivotal connection between said first and second links and said pivotal connection between said second link and said other valve means. 